The recent Final Monograph published by the U.S. Food and Drug Administration (FDA) mandates that sunscreens without broad spectrum UV protection must include the statement, “Skin Cancer/Skin Aging Alert: Spending time in the sun increases your risk of skin cancer and early skin aging. This product has been shown only to help prevent sunburn, not skin cancer or early skin aging.” As many sunscreen manufacturers rush to reformulate their products to provide broad spectrum coverage to avoid the warning label; however, they should be aware that recent research suggests that warning labels may not scare consumers away.

Scientists at INSEAD in Singapore, Tel Aviv University and New York University have found that rather than scaring consumers away, warnings on drug labels can improve consumers’ opinions and increase product sales when there is a delay between seeing the ad and deciding to buy or consume the product.

In the September 2013 issue of Psychological Science, psychological scientist Ziv Carmon (INSEAD), Yael Steinhart (Tel Aviv University) and Yaacov Trope (New York University) tested their hypothesis that warning labels might have a reverse affect on consumers in four experiments.

In one experiment, smokers saw one version of a cigarette ad included a warning that smoking causes lung cancer, heart disease and emphysema, while another version did not include the warning. Participants who had the opportunity to purchase the cigarettes soon after seeing the ad bought less if the ad they saw included the warning. In contrast, participants who were given the opportunity to purchase the cigarettes a few days later bought more if the ad included the warning.

The same outcome emerged when the researchers ran a similar experiment with ads for artificial sweeteners. According to Carmon and his colleagues, the warnings backfired because the psychological distance created by the delay between exposure to the ad and the customer decision made the side effects seem abstract—participants came to see the warning as an indication of the firm’s honesty and trustworthiness. In fact, participants evaluated drugs for erectile dysfunction and hair loss that had potentially serious side effects more favorably, and as more trustworthy, when they were told the products weren’t on the shelves yet.

While conventional wisdom suggests that explicit warnings about dangerous side effect will make people think twice before taking medical risks, these findings suggests otherwise. The researchers believe that their findings are important because these kinds of warnings accompany many consumer products beyond medications.